This is a working overview of method validation, written for readers who want more than a one-paragraph summary but less than a textbook.
Reviewed 2025-09-30. Anything still debated is marked as such rather than presented as settled.
Method validation examines whether an HPLC procedure is suitable for its intended purpose. Common parameters include accuracy, precision, specificity, linearity, range, detection limit, quantification limit, and robustness. Accuracy describes closeness to a true or accepted value, while precision describes agreement among repeated measurements. Specificity shows whether the method can measure the analyte without interference from related substances. Robustness tests small deliberate changes in flow, temperature, or solvent composition. Validation is not a one-time event; methods may need partial revalidation after changes to instruments, columns, sample handling, or specification limits. Regulatory guidance provides frameworks, but some details remain method-specific.
Regulatory and pharmacopeial texts shape how HPLC testing is performed and documented. The International Council for Harmonisation provides validation guidance, while pharmacopeias publish general chromatography chapters and monographs for specific materials. Accreditation standards such as ISO/IEC 17025 address laboratory competence and traceability. Inspectors may review instrument qualification, analyst training, reference material control, and electronic records. Open questions include how best to validate methods for new complex products and how to handle automated data processing. Laboratories generally resolve these issues through risk assessment, method lifecycle management, and documented scientific justification.
Documentation and traceability are central to regulated HPLC testing. Records typically include instrument logs, column history, mobile-phase preparation, sample preparation, injection sequences, raw chromatograms, and audit trails. Electronic systems may require user access controls, time-stamped changes, and backup procedures. Training records show that analysts are qualified for assigned methods. Audits and inspections check whether written procedures match actual practice and whether deviations are documented. These controls support reproducibility and allow results to be reconstructed if questions arise later.
Method validation establishes that an HPLC procedure is suitable for its intended purpose. Typical parameters include accuracy, precision, specificity, linearity, range, limit of detection, limit of quantitation, robustness, and solution stability. Accuracy reflects closeness to a reference value, while precision reflects agreement among repeated measurements. Specificity shows whether the method can measure the analyte without interference from matrix components. Validation is documented through protocols and reports, and the required extent depends on the method's use and regulatory context.
Routine quality control uses system suitability, blank injections, check standards, and control samples to detect drift or contamination. System suitability criteria may specify minimum resolution, maximum tailing factor, and a permitted range for repeated injections. Blank injections reveal carryover or solvent contamination, while check standards confirm calibration accuracy over a batch. Control samples with known analyte levels can show whether results remain within statistical limits. When a control result falls outside limits, the analyst investigates the cause and may invalidate affected results before repeating the batch.
| Property | Value | Notes |
|---|---|---|
| Primary guidance | ICH Q2(R2) | Analytical procedure validation |
| Compendial chapter | USP <621> | Chromatography general chapter |
| Validation parameter | Accuracy | Closeness to accepted true value |
| System suitability check | Peak resolution | Ensures separation between adjacent peaks |
| Data record | Audit trail | Supports data integrity and traceability |
Separation performance depends on particle size, pore size, column length, and the chemistry of the stationary phase. Smaller particles generally improve efficiency but require higher pressure and suitable instrumentation. The mobile phase often contains buffers and organic solvents that influence retention and selectivity. Testing labs select conditions based on the analytes, sample matrix, and required sensitivity. Method development frequently involves screening several columns and solvent mixtures before a final set of conditions is chosen.
High-performance liquid chromatography is an analytical technique that separates components in a liquid sample by passing them through a packed column under pressure. A pump delivers a mobile phase at a controlled flow rate, and an injector introduces the sample into the stream. Differences in how analytes partition between the mobile phase and the stationary phase cause them to exit the column at different times. Detection then records a signal proportional to the amount of each separated substance. The resulting chromatogram provides retention times and peak areas for identification and quantification.
==== Declined ==== Jasmine Crockett, incumbent U.S. representative (ran for U.S. Senate) Domingo García, former president of the League of United Latin American Citizens (2018–2024) and candidate for this district in 2012 Marc Veasey, incumbent U.S. representative from the 25th district (ran for Tarrant County judge)
=== Artistic === Blood is one of the body fluids that has been used in art. In particular, the performances of Viennese Actionist Hermann Nitsch, Istvan Kantor, Franko B, Lennie Lee, Ron Athey, Yang Zhichao, Lucas Abela and Kira O'Reilly, along with the photography of Andres Serrano, have incorporated blood as a prominent visual element. Marc Quinn has made sculptures using frozen blood, including a cast of his own head made using his own blood.
== Further reading == "Electronic nicotine delivery systems" (PDF). World Health Organization. 21 July 2014. pp. 1–13. Linda Bauld; Kathryn Angus; Marisa de Andrade (May 2014). "E-cigarette uptake and marketing" (PDF). Public Health England. UK. pp. 1–19. McNeill, A; Brose, LS; Calder, R; Bauld, L; Robson, D (February 2018). "Evidence review of e-cigarettes and heated tobacco products 2018" (PDF). Public Health England. UK. pp. 1–243. McNeill, A; Brose, LS; Calder, R; Hitchman, SC; Hajek, P; McRobbie, H (August 2015). "E-cigarettes: an evidence update" (PDF). Public Health England. UK. pp. 1–113. National Academies of Sciences, Engineering, and Medicine; et al. (Committee on the Review of the Health Effects of Electronic Nicotine Delivery Systems) (January 2018). Stratton, Kathleen; Kwan, Leslie Y.; Eaton, David L. (eds.). Public Health Consequences of E-Cigarettes. Washington, DC: National Academies Press. Bibcode:2018nap..book24952N. doi:10.17226/24952. ISBN 978-0-309-46834-3. PMID 29894118. Retrieved 15 January 2023. Summary National Center for Chronic Disease Prevention Health Promotion (US) Office on Smoking Health (2014). The Health Consequences of Smoking—50 Years of Progress: A Report of the Surgeon General. Surgeon General of the United States. pp. 1–943. PMID 24455788. "State Health Officer's Report on E-Cigarettes: A Community Health Threat" (PDF). California Tobacco Control Program. California Department of Public Health. January 2015. pp. 1–21. This article incorporates text from this source, which is in the public domain.
Drug Delivery: Developing Countries The drug delivery mechanisms have the potential to enhance the health of all parts of the world despite the fact that most of the advanced systems are quite costly to the poor nations. Simple system, orals or skin patch, is more feasible in low resource countries. Most countries have used vaccines that are administered orally to combat such diseases as polio (Yenet et al., 2023). The government and the hospital organizations need to collaborate in order to reduce the cost and offer the new means of drug distribution that will allow giving the new medications everywhere. Ethical and Safety Issues Emerging drug delivery devices such as nanoparticles or gene therapies are highly dangerous in terms of safety and equity. For example, we should make sure that the treatments would not negatively affect the environment or cause any incidental side effects. The regulation of other agencies such as FDA are applied in the process of ensuring the safety of new practices but vary across countries (World Health Organization, 2024). The government has the mandate of making sure that medicine is not only affordable to the wealthy members of the society, but also to the vulnerable ones as well. The issue of drug delivery has raised a number of ethical concerns with respect to patients and healthcare systems. One common concern is the accessibility of specific medications within a health organization.
In October 2015, John Carreyrou of The Wall Street Journal reported that Theranos was using traditional blood testing machines instead of the company's Edison devices to run its tests, and that the company's Edison machines might provide inaccurate results. Tyler Shultz, a Theranos employee from 2013 to 2014 and the grandson of then–Theranos director, former U.S. Secretary of State George P. Shultz, was a key source for the WSJ story. Shultz had attempted to take his concerns to company management. When that failed, he had spoken to Carreyrou and also, under an alias, reported the company to the New York State Department of Health for CLIA violations. Theranos claimed that the allegations were "factually and scientifically erroneous". Walgreens suspended plans to expand blood-testing centers in their stores following the report. At that time, the Cleveland Clinic announced that it would work to verify Theranos technology. Theranos fought back against the Journal's investigation, sending lawyers after sources in the story, including Shultz, in an effort to stop them from providing information to the press. Former employees of reputation management firm Status Labs said that Theranos had hired the firm to discreetly erase mentions of the WSJ's reporting from its Wikipedia article (the activity being a violation of the website's terms of use). Following the WSJ story, the history of FDA interactions with Theranos was scrutinized. The FDA had received a formal inquiry to look at Theranos blood test devices by the U.S.
Sources: en.wikipedia.org
=== Name === Within the INN, USAN, BAN, and AAN naming systems this drug is known as butorphanol, while within JAN it is named torbugesic. As the tartrate salt, butorphanol is known as butorphanol tartrate (USAN, BAN).
=== SARS-CoV-2 === Rapamycin has been proposed as a treatment for severe acute respiratory syndrome coronavirus 2 insofar as its immunosuppressive effects could prevent or reduce the cytokine storm seen in very serious cases of COVID-19. Moreover, inhibition of cell proliferation by rapamycin could reduce viral replication.
Many different foods can be prepared by dehydration. Meat has held a historically significant role. For centuries, much of the European diet depended on dried cod—known as salt cod, bacalhau (with salt), or stockfish (without). It formed the main protein source for the slaves on the West Indian plantations, and was a major economic force within the triangular trade. Dried fish most commonly cod or haddock, known as Harðfiskur, is a delicacy in Iceland, while dried reindeer meat is a traditional Sámi food. Dried meats include prosciutto (Parma ham), bresaola, biltong and beef jerky. Dried fruits have been consumed historically due to their high sugar content and sweet taste, and a longer shelf-life from drying. Fruits may be used and named differently when dried. The plum becomes a prune, the grape a raisin. Figs and dates may be transformed into different products that can either be eaten as they are, used in recipes, or rehydrated. Freeze-dried vegetables are often found in food for backpackers, hunters, and the military. Garlic and onion are often dried and stored with their stalks braided. Edible mushrooms are sometimes dried for preservation or to be used as seasonings.
On 29 September P.W. Botha added a third objective to Operation Moduler: the destruction of all FAPLA units east of Cuito Cuanavale. The reasons for this shift in objectives once FAPLA had abandoned its offensive were not apparent to everybody in the South African government. Pik Botha and his senior colleagues in the foreign ministry cautioned against a major offensive north of the Lomba, citing potential diplomatic repercussions. But confidence in the SADF had been buoyed by its effective defence of the Lomba, and members of the South African general staff successfully agitated for a renewed offensive towards Cuito Cuanavale. It is unclear whether they interpreted their new objective as veiled permission to seize Cuito Cuanavale itself, although the option was discussed. Per Botha's new directive, the SADF commenced Operation Hooper with the goal of encircling the retreating Angolan brigades and preparing for operations further east of the Cuito River. The decision to commence Hooper towards the end of the 1987 calendar year created problems for the SADF, since a number of white conscripts involved in the Lomba River engagements were nearing the end of their national service. This led to a delay of several weeks while the existing troops were gradually withdrawn from Angola and replaced with a new intake. The SADF had dispatched a second mechanised battalion, 4 South African Infantry, to Angola, as well as a squadron of Olifant Mk1A tanks and a battery of G5 and G6 howitzers.
oligonucleotide Also abbreviated oligo. A relatively short chain of nucleic acid residues. In the laboratory, oligonucleotides are commonly used as primers or hybridization probes to detect the presence of larger mRNA molecules or assembled into two-dimensional microarrays for high-throughput sequencing analysis.
Sources: en.wikipedia.org
System suitability is a set of checks performed before and during an HPLC run to confirm that the instrument and method are working as expected. It may include retention time repeatability, resolution between peaks, peak symmetry, and signal intensity. Failing suitability criteria usually invalidates the run.
An HPLC method is typically validated before its routine use and revalidated in part when significant changes affect the method. Regulators do not set a universal calendar interval. The need for revalidation depends on the change, its risk, and the applicable guidance.
Validation establishes that a method is suitable for its intended purpose, often through a planned study. Verification confirms that a laboratory can reproduce a previously validated or compendial method under its own conditions. Verification is usually narrower than full validation.
Validation establishes suitability for a new method, while verification confirms that a method works in a specific laboratory. Verification is often used when a validated method is adopted with existing equipment and staff. Both rely on documented acceptance criteria.